Sonny Bill Williams is back in the All Blacks squad for the Rugby Championship.

After crushing the Welsh in three Tests in June, the selectors have made no changes to the 18 forwards from that series.

In the backs, the 16-strong group has been reduced to 14, with Damien McKenzie and Seta Tamanivalu being dropped and Charlie Ngatai not considered with his ongoing concussion symptoms.

Williams will join the squad after his sevens appearances at the Rio Olympics and won't likely be available for the first championship Test.

"It was more a case of who do we leave out, rather than who do we pick," coach Steve Hansen said on Monday.

The number one goal was to win the championship but there were also secondary goals, he said.

"One is to re-establish our team, from a leadership and playing point of view. The second goal is to grow the understanding and confidence of our newer players, both on and off the track; and thirdly, we want to play a standard of rugby that we can all be proud of and excited by."

The championship opponents would require a growth in physicality, intensity and the standard of preparation, Hansen said.

"How well we do that will be reflected in our results."

The squad has a total of 968 Test caps.

It is made up of five Blues players, six Chiefs, five Hurricanes, nine Crusaders and seven Highlanders.

The squad will assemble on Thursday this week for a two-day camp in Auckland minus the five Hurricanes who are preparing for Saturday's Super Rugby final.